N-acetonyl-pyridinium chloride as an azo coupling component in diazotypes



Patented Nov. 21, 1950 N-AOETONYL-PYRIDINIUM CHLORIDE AS AN AZO CDUPLIN G COMPONENT EN DIAZO- TYPES Andre E. Van Dcrmael, Heverlee (Louvain), Bel- .gium,

assignor to Gevaert Photo-Producten N. V., Antwerp-Mortsel, Belgium, a company of Belgium No Drawing. Application July 29, 1946, Serial 1 Claim.

This invention relates to a process for preparing diazotypes.

The primary object of this invention is to provide a color coupler to be used in the preparation of diazotypes which is of great effectiveness.

Other objects will appear from the following description.

In diazotype processes, mono or polyhydroxy compounds as, for instance, resorcinol and phloroglucinol are chiefly used as coupling compounds.

It has also been proposed to use coupling components of the following formula:

wherein R represents aryl, alkyl or aralkyl; X represents H, aryl, alkyl, aralkyl, acyl or a hydroaromatic residue; and Y represents H, aryl, alkyl, aralkyl, acyl or a hydroaromatic residue.

All these coupling components produce with the usual diazo compounds dyestufis which form a more or less intense image. Regarding the second named group, it is said to offer the special advantage of being usable mixed with other components givin hereby opaque neutral colors.

It has been found that all organic compounds which contain a reactive methyl group are well suited as coupling components in the preparation of diazotypes, whereby known and commonly used diazo compounds may be "used as light-sensitive compounds.

According to this invention, I employ N- acetonyl-pyridinium chloride as a coupler.

The most important characteristics of my new coupling component is its great solubility and its quality of rapidly coupling and giving very intense dyestuffs with the usual diazo compounds.

The coupling element of my invention may be used singly or in any combination. Whenused in mixtures, diazotypes of very intense neutral color are obtained whereas, for instance, the use of phloroglucinol alone produces only a brown violet color.

The following example will serve to further In Belgium August 3, 1945 illustrate my invention but it is to be understood that this invention is not limited to the example iven.

EwampZe.-To a suitable paper is applied a solution of 1.5 g. of diazonium compound from p-diethylamino aniline, 1 g. of tartaric acid, 0.8 g. of aluminum sulphate, 0.15 g. of phloroglucinol and 0.08 g. of N-acetonylpyridinium chloride in cm. of water.

The paper is exposed through a diapositive and developed in an ammoniacal atmosphere. A

sharp black print is obtained.

The paper is exposed through a diapositive and developed in an ammoniacal atmosphere. A dark magenta print is obtained.

My new coupling component may be added either to the developer when the half-wet process is used, or to a solution which contains one or more diazo compounds and which is applied as light-sensitive layer to an adapted paper.

When used alone, it produces in both cases chiefly colored images. By using a mixture, it is possible to obtain all the desired colors and also practically complete neutral images.

Due to the great variety of my coupling component, all colors are obtainable and all coupling methods are usable so that multicolored images can easily be obtained.

I claim:

In the preparation of diazotypes, the method which comprises selectively exposing a lightsensitive material containing a light-sensitive diazo compound, and coupling the diazo compound retained in the unexposed areas with N- acetonyl-pyridinium chloride.

ANDRE E. VAN DORMAEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Num er Name Date 1,822,065 Sprongerts Sept. 8, 1931 2,027,229 Hinman Jan. '7, 1936 2,154,918 Schneider et a1. Apr. 18, 1939 2,217,189 Sus Oct. 8, 1940 2,331,326 Kendall Oct. 12, 1943 2,405,523 Sease Aug. 6, 1946 

